No dirt particles in the board

Andreas Welle examines the production of playing card board.

Question: Mr Welle, every child is familiar with the range of card games. Not many people know, however, that the paper is not produced as small rectangles, but comes out of the paper machine as a roll weighing several tons. But how exactly is this roll made?

Andreas Welle: The first step takes place in the central pulp preparation plant. There, the pulp is dissolved and combined with other materials to form a suspension: a substance-water mixture.

Do you use a special pulp for the playing card board?

We only use eucalyptus pulp for the production of our playing card board. Over the years, this pulp has proven to give the board the necessary stiffness, which later becomes very important.

Is this stiffness achieved only with the pulp?

Needless to say, it's not. It's also because of what we do with the pulp. The pulp-water mixture is fed into a grinding machine, where the pulp mass is fed into a refiner between static and moving blades. The pulp fiber is squashed and shortened here. This is necessary for the 'snap'.

I'm guessing this has something to do with the finished playing card?

Exactly. The snap or restoring force refers to a playing card's ability to always return to its original position. A distinction is made between a 'snap' and a 'persistent snap'. A persistent snap refers to how often playing cards can be bent, which happens while shuffling, before they no longer snap back into their original position.

But before we can shuffle, we have to return to production. What happens after the grinding machine?

After the grinding machine comes the paper machine, where the mass is again diluted and evenly distributed on a sieve. It is important here that the distribution is as even as possible. It must look like frosted glass, with absolutely no clouding. The aim of the grinding is to add flexibility to the fiber. For the required stiffness and hardness, starch is now added, like in former time when ironing. The board is also coated twice in the paper machine.

Once on each side?

No, twice on the same side. First the board gets a pre-coating, then an additional topcoat using a special application technology. After coating, the board is smoothed.

Koehler manufactures card board in various qualities. Is the manufacturing method always the same?

That's right, we produce our card board in Casino Classic, Casino Imperial and other qualities. Especially for certain markets where there is a demand, we also offer uncoated board. In the case of coated varieties, it can be said that the snap and persistent snap get better as the quality increases. This also has something to do with the fact that we impregnate the board while it is still in the paper machine.

Presumably, the paper machine is not the end of the production process. If you tear a card made of Koehler board, you can see a black intermediate layer. Where does this come from?

That's right. When the board comes out of the paper machine, we initially have a roll that weighs over eight tons. If we were to unroll this, it would be up to 18 kilometers long, depending on the board's grammage. We take two of these rolls, called tambours in technical jargon, and glue them together with black or blue glue.

This explains why the board is only coated from one side. It is not possible to make a double-sided coated layer that is thick enough?

It is theoretically possible. However, the adhesive gives us an important aspect: namely, opacity. This means that I can hold a printed card against the light with the back to my eyes, but I cannot see its value on the front. Without the black or blue colored adhesive, I would be able to see this.

Is the big roll now shipped?

No, we only ship a few rolls these days. We usually cut the product into the format that the customer needs. To do this, the rolls are fed into a sorting sheeter, where they are cut into large sheets according to customer requirements. The formats differ from customer to customer. This has to do with the fact that, all over world, playing cards do not always have the same size and also the number of cards in the deck is different. A finished printed sheet always contains a complete deck of cards.

You mentioned opacity. With the quality of the world's casinos in mind, it must be important that the board always looks the same?

That's right. The paper must be of the highest purity. It must contain no dirt particles, nor any impressions of any kind. Any impurity carries the risk that the card will be viewed as marked in the casino. And a lot of money is at stake there or, if we are to believe Hollywood, even life and death. However, we can be sure that this won't happen with our playing card board.